We are going to sing the woad song (see the Digital Tradition)for the St David's Society, and I need some background about Celts (if any) painting themselves blue.

I thought that Julius Caesar said in his "Gallic Wars" that the Celts painted themselves blue for battle. Strangely, enough my encyclopedia doesn't mention this in the article on Caesar. So I would like to ask:

Did this quotation really come from Casesar's Gallic Wars?
What do the surviving manuscripts actually say?
Did he ever get to Britain (i.e. did he ever see any blue warriors with his own eyes?)

Over the years, I have read that the reference really means that they wore woollen clothes, they had tattoos, or they wore war paint.

I have seen the SCA site which discusses tattoos,Priteni and Picts, and I have read the Mudcat threads on the history of the song. I just need info on how the legend of blue warriors came about.

Thanks.